Bussing

Bussing is a mixing technique where multiple audio signals are routed to the same place. That place is called a bus.

The most common example of a bus is the master bus. Just about every mixing console or DAW has a master bus where all signals go before they are sent to audio output devices like speakers. On the master bus you can control the volume with a fader and sometimes you can also add processing.

Mixing consoles and DAWs also sometimes allow you to create your own buses where you decide which audio signals are sent to them. If an engineer says they are bussing one or more tracks to an effect, that means they have created a bus and decided which signals are routed into it and have added an effect to the combined signal.

Why Is Bussing Important For Mixing?

Bussing gives you better control over the mix. It allows you to apply processing and control volume of groups of tracks while retaining the same balance between them.

If you want to change the volume of the entire drum kit, you can increase the volume of each individual drum mic. But if you take this approach, you will likely alter the balance of volumes within the drum kit. If you want to raise or lower the volume of the entire kit and retain the balance, a bus is the best option.

The same principle applies to group processing for effects like reverb. It is often useful to increase or decrease the amount of processing on the whole group while maintaining the balance within the group.

Bussing can also help to keep your DAW from crashing your computer. If you want to add a long echo to ten singers, you can add the effect once on each singer channel or you can route them all to a bus and add the effect once. Having one echo effect instead of ten puts a lot less strain on your CPU.

What Is The Glue Effect?

Bussing does something special to the actual sound of your music. When you take many separate tracks and send them through the exact same processing, they start to feel more connected to each other.

Mix engineers do this all the time with drums. They will put a gentle compressor on the drum bus. When the kick drum, the snare drum, and the cymbals all hit this same compressor, they sound a little bit more like a cohesive instrument than independent drum samples playing together.

Engineers call these shared effects “glue.”